Telephone-transmitter.



l PATENTBD MAR. a, 1903. L. MBLLETT. TELEPHONE TRANSMITTER.

' APPLICATION FILED JUNE 6, 19.0.2.

l0 MODEL.

WITNSEE 5 5.

VUNITED STATES lPATENT OFFICE.

LEMUEL MELLETT, OF SOMERVILLE, MASSACHUSETTS, ASSIGNOR, BY DIRECT ANDMESNE ASSIGNMENTS, TO MICROPHONE TRANSMITTER COMPANY, OF BOSTON,MASSACHUSETTS, A CORPORATION OF MAINE.

TELEPHONE-TRANSM ITTER.

SPECIFICATION forming part of Letters Patent No. 721,817, dated March 3,1903. Application lecl June 6, 19,02- Serial Nor110,467. (No model.)

To a/ZZ- whom it may concern:

Be it known that I, LEMUEL MELLETT, of Somerville, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Telephone- Transmitters,of which the followingisa speci; ication.

This invention relates to telephone-transmitters; and its object is toobtain greater 1o delicacy or receptiveness in the instrument with aconsequent increase in the loudness and distinctness of the sounds givenout at the receiving end of the line. This object I attain by dispensingwith the ordinary diaphragm as the primary sound-receiving element ofthe transmitter and employing in its place a primary sound-receiver,consisting of a plurality of mechanical vibrators, preferably attuned tothe notes of the scale and prozo vided in sufficient number to take upall or the principal tones of the speaking voice, such vibratorscontrolling the resistance-varying means, preferably by directattachment to the movable electrode. .v Y

The accompanying drawings represent an embodiment of my invention whichI have selected for illustration, but to the details of which I do notconfine myself.

Figure 1 represents an axial. section of a 3o transmitter constructed inaccordance with my invention. Fig. 2 represents a sectionon line 2 2 ofFig. 1. 1 Y

The same reference characters indicate the same parts in both figures.

In the drawings, 10 is a casing having a mouthpiece 11,immediatelybehindandin line with which is located a hub or support 12, from which radiatea series of vibrators 13 13, consisting of helically-coiled Wiresprings. 4.o These springs are of different lengths and attuned to thenotes of the scale, and I have shown two octaves, although not confinedto the exact number or arrangement shown, nor to any preciseconstruction of vibrators. These springs besides responding as a Wholeto fundamental tones will also respond sympathetically to a large rangeof harmonics. The hub 12 is connected by a stem 14: with the diaphragm21, hereinafter mentioned, and

l 5o therethrough with the movable electrode 15 of the ordinaryresistance-varying cell or element 16. Y

17 is the back electrode, supported by a rigid bridge 18, and 19 isgranular carbon interposed between the electrodes.

2O is a flexible sheet of mica connecting the movable walls4 of thecarbon-cell with the fixed electrode. The walls of the cell 16 are shownas continued or spread out into a diaphragm 21, forming a support for.the movable electrode 15 and the vibrators 13, which permits theelectrode t0 travel readily with the movements imparted by thevibrators.

22 is a partition forming the back wall of a chamber 23 in which thevibrators 13 are placed. The vibrators 13 receive in a primary capacitythe air vibrations due to sounds,\and owing to their great delicacy theyabsorb these vibrations and are themselves set in vibration more readilythan is the case with the ordinary transmitter-diaphragm. The latterbeing relatively stiff refiects a large part of the sound-waves receivedupon it, which reflected sound is not eiciently utilized in vibratingthe movable electrode.

.The construction above described may be varied in many particularsWhile still retaining the principle of. operation involved.

The function of the diaphragm 21 is merely to actas a ilexible supportfor the movable electrode, and any other'suitable means for movablysupporting said electrode may be substituted in its place.

-I am aware that harmonic vibrators have heretofore been used in variousconnections with respect to telephonie apparatus; but I am not aware ofthe use of' mechanical vibrators prior to my invention as a primarysound-'receiving device.

By the expression primary sound receiver or its equivalents used hereinI mean that device iirst in the path of the air soundwavesr aecting theresistance varying means.

This application discloses certain structures which I do not hereinclaim or claim generically, as the same are incorporated in anotherapplication, Serial No. 113,556, iiled by me.

I claim- IOO varying elementI having a movable electrode, a primarysound-affected device consisting of a plurality of vibrators, and aflexible support located behind said vibrators and supporting the latterand the movable electrode.

In testimony whereof I have axed lny signature in presence of twowitnesses.

LEMU EL MELLETT.

Witnesses:

R. M. PIERSON, ADELINE C. RATIGAN.

